This invention relates to surface-processing apparatus, and more particularly to a self-balanced apparatus wherein a surface-processing toll engages the surface to be processed at a preselected uniform pressure, regardless of surface irregularities, or the orientation of the surface-processing apparatus to the work surface.
My prior patent, U.S. Pat. No. 4,305,344 discloses a surface-processing apparatus including an elongated, pliant track which is curved to conform to the general contour of an aircraft fuselage or other surface to be processed. A carriage reciprocates along the track and mounts a surface-processing tool, which may be a painting or sanding apparatus, or the like.
In working on a sensitive-to-damage surface such as an aircraft fuselage, it is very desirable that the surface-processing tool engage the surface at a very exact preselected pressure. Further, the tool should be moved along the surface at a substantially constant rate. This is to insure that the proper amount of processing is achieved, uniformly over the surface, without damaging the sensitive surface.
It is also desirable that the track or other support means for the surface-processing tool be entirely separate from the surface itself. The processing operations require a delicate and controlled touch, and consequently nothing which may distort the work surface may be allowed to contact it. Since this precludes the use of external sensors which touch the workpiece, the track and surface-processing tool must be capable of positioning independently of such devices.
The prior art discloses surface-processing apparatus for work on slabs or rods which may have irregular contours. In such apparatus, the rods or slabs are passed through the apparatus, which accordingly is not applicable to the surface processing of large work pieces such as aircraft bodies and ship hulls, where the apparatus must be passed over the surface of the work.
Further, in the latter application the orientation of the surface-processing tool is continuously changing, which introduces further and unique problems.
Accordingly, it is the general object of the present invention to provide a high capacity surface-processing apparatus which traverses and engages an irregular work surface with a constant, preselected pressure.
Another object is to provide such an apparatus which is balanced to work equally well in all orientations.
Yet another object is to provide means for establishing accurately the position of a track supporting a surface-processing tool, relative to the surface to be processed.
Another object is to provide a carriage for traversing the track and carrying the surface-processing tool along a work surface strip of predetermined extent.
A further object is to provide extension means for accomodating any large-scale variation at different points in the distance between the tool-supporting track, and the adjacent work surface.
Yet another object is to provide sensitive apparatus which quickly and positively compensates for minor or suddenly-encountered irregularities in the contour of the work surface.
A further object is to provide an apparatus adjustable to have a very delicate and controlled touch for processing surfaces which previously could be worked on only by hand.
A still further object is to provide a surface-processing apparatus in which the surface-processing tool is its own sensor of proximity to the work surface.
These and other objects and advantages of the present invention and the manner in which they are achieved will be made apparent in the following specification and claims.